Coupling means for coaxial cables



Dec, 22, 1942. w A BRUNO COUPLING MEANS FOR (JO-AXIAL CABLES Filed Dec. 3, l94l- Y 'M Mv a i A TTO R N E Y Patented Dec. 22, 1942 COUPLING MEANS FOR COAXIAL CABLES William A. Bruno, Astoria, Long Island, N. Y., as-

signor to Bruno Patents Inc., Long Island City,

Application December 3, 1941, Serial No. 421,453

7 Claims.

This invention relates to high frequency coaxial cables, such as radio-frequency cables, and more particularly to means for joining together the sections of the outer conductor in such coaxial cables.

High frequency coaxial cables consist of an inner conductor which is coaxially surrounded by a tubular outer conductor, the inner and outer conductor being spaced a certain distance apart.

Joints in the outer conductor of coaxial cables can be made by soldering or the like. The sections of such soldered cables, however, cannot be quickly assembled or taken apart. Instead of making permanent connections by soldering, the adjacent ends of the conductor sections may form joints, which are held together by screws or bolts, for example. It has been found, however, that in the joints of this type hitherto used the inner surfaces of the outer conductor sections do not present a satisfactory low loss elec trical path, particularly in an ultra-high frequency circuit.

It is the main object of the present invention to provide an improved coupling means for the outer conductor sections in coaxial cables, said coupling'means being adapted to be quickly assembled and taken apart, and to provide a low loss electrical path which does not cause incon-t veniences in an ultra-high frequency circuit. Another object of the invention is to provide a coupling means which forms a satisfactory gaseous seal between the outer conductor sections of a coaxial cable to be connected.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention may best be understood by reference to the accompanying drawing, in which some embodiments of my invention are shown for illustrative purposes, and in which:

Fig. 1 is a sectional view of a coupling means for coaxial cables embodying the invention;

Fig. 2 is a cross-section of the coupling means shown in Fig. 1, the section being taken along line 22;

Fig. 3 shows a preferred embodiment of this invention partly in section, and partly in elevation, and Fig, 4 is an end view of the coupling means shown in 'Fig. 3, and

Fig. 5 ShOWs a modified form of the embodiment shown in Figs. 3 and 4.

The inner conductor which may be of any suitable type, is not shown in the drawing.

Referring now to Figs, 1 and 2, section I of an outer conductor of an ultra-high fre- I quency coaxial cable is provided with an end member I, while the adjoining section 2 of said coaxial cable is provided with an end member 2. These end members are connected with the respective sections I and 2, for example by soldering. Member I' is provided with a projecting ring portion 3 and has a bevelled, inwardly tapering end portion 4. Member 2' is formed with a shoulder 5 provided with a screwthread 6. This member 2' has an outwardly tapering inner end portion [0, said end portion l0 being adapted to receive the inwardly tapering end portion 4 of section I. As indicated in Fig. 1 the angle formed by conical surface 4 and the axially extending inner cylindrical surface of end piece I is slightly smaller than,the corresponding angle formed by the conical surface of end portion IO' and the axially extending inner cylindrical surface of end piece 2', the difference between said angles preferably amounting to about 2-3. End portions l and 2' may be brought into tight engagement by means of clamping nut 8 which is provided with thread 9.

Owing to this shape of the adjoining end pieces, electrical contact is formed in the joint at the inside of the outer conductor at 1 only, and the continuous, smooth inner surface of the joined outer conductor sections thus formed, represents an electrical path which does not cause substantial evolution of heat and the occurrence of losses in an ultra-high frequency circuit in which the coaxial cable here shown may be used.

I have further found that joining of memdividual sections'of an outer conductor, and the obtaining of safe and permanent electrical connections of the above described type is facilitated by shaping the adjacent end members of the outer conductor sections to be united in such a manner that the end member provided with an inwardly tapering conical end portion, such as 4, is also provided with a cylindrical surface which fits into a corresponding cylindrical bore of the adjoining end piece which has an inwardly tapering conical inner end portion, such as 10. This preferred embodiment of the invention is shown in Figs. 3 and 4.

Referring now particularly to Fig. 3, end member l of an outer section of a coaxial cable is provided with a bevelled inwardly tapering end portion 4, and with an adjacent cylindrical portion I4, which extends in axial direction. End member 2' is provided with an outwardly tapering inner end portion band an adjacent inner cylindrical portion lifwhich extends in axial direction. This cylindrical portion is adapted to receive said cylindrical portion I4 of end member I, and serves as a guide for end member I. This end member I is also provided with a recess I6, which is adapted to receive a corresponding projecting part H of end member 2' in spaced relation so that a suitable packing element, such as a neoprene gasket I8 may be inserted between said projecting part I"! and recess l6. End members I and 2' are flanged. and their flanges I I and I2 are adapted to receive cap screws I9, for bringing the end members into tight engagement. Split washers 20 are interposed between the heads of said screws and the flange II. As shown in Fig. 3, the angle of the conical surface 4 is somewhat smaller than the angle of conical surface It], and electrical contact is formed in the joint at the inner sur face of the outer conductor at 7 only.

The modification shown in Fig. 5 is substantially similar to that shown in Figs. 3 and 4. In this modification, however, end members i and 2 are clamped together by means of a threaded clamping nut 8. The handling of such clamping nut requires the use of a relatively large tool, while screws I9 shown in Figs. 3 and 4 can be tightened or removed by means of a relatively small wrench. I prefer, therefore, the use of such screws particularly in cable joints, which are not or ditficultly accessible to a relatively large tool.

It will be understood that this invention may be carried out in other specific ways than those herein set forth and the embodiments shown should be, therefore, considered as illustrative and not restrictive within the spirit of the invention as defined in the appended claims.

As shown in the above figures, a contact is formed by the end. members I and I at the tips of their conical portions. Thus, the inner surfaces of the outer conductor sections, and the inner surfaces of the end members form an unbroken cylindrical surface having substantially the same inner cross-section throughout the outer conductor sections and the coupling means.

This coupling means also forms a gas tight connection between the individual sections of the outer connector.

I claim:

1. A coupling means for outer conductor sections of a coaxial cable, said coupling means comprising two end members; each of said end members being adapted to be connected with one end of outer conductor sections to be joined; one of said end members being provided with an inwardly tapering conical end portion which fits into an outwardly tapering conical bore of the other end member; the angles formed by the cable axis, and by the surface of said inwardly tapering conical end portion, and the surface of said outwardly tapering bore, respectively, being slightly different; a contact between the assembled end members being formed at the tips of their conical end portions; the inner surfaces of the outer conductor sections, and the inner surfaces of the end members being adapted to form an unbroken, cylindrical surface having substantially the same inner cross-section throughout the outer conductor sections and the coupling means; means adapted to bring said end members into tight engagement.

2. In a coupling means for outer conductor sections of a coaxial cable, two end members; each of said end members being adapted to be connected with one end of outer conductor sections to be joined; one of said end members being provided with an inwardly tapering conical end portion, and the other of said end members being provided with a registering outwardly tapering conical bore adapted to receive said inwardly tapering end portion; the angle formed by the conical surface in said one end member and the cylindrical inner surface thereof, being slightly smaller than the angle formed by the conical surface of said other end member and the cylindrical inner surface thereof; a contact between the assembled end members being formed at the tips of their conical end portions; the inner sufaces of the outer conductor sections, and the inner surfaces of the end members being adapted to form an unbroken, cylindrical surface having substantiall the same inner crosssection throughout the outer conductor sections and the coupling means; means adapted to bring said end members into tight engagement.

3. In a coupling ineans for outer conductor sections of a coaxial cable, two end members; each of said end members being adapted to be connected with one end of outer conductor sections to be joined; one of said end members being provided with an inwardly tapering conical end portion, and the other of said end members being provided with a registering outwardly tapering conical bore adapted to receive said inwardly tapering end portion; the angle formed by the conical surface in said one end member and the cylindrical inner surface thereof, being slightly smaller than the angle formed by the conical surface of said other end member and the cylindrical inner surface thereof; a contact between the assembled end members being formed at the tips of their conical end portions; the inner surfaces of the outer conductor sections, and the inner surfaces of the end members being adapted to form an unbroken cylindrical surface having substantially the same inner crosssection throughout the outer conductor sections and the coupling means; said one end member being provided on its outer surface with a projecting ring member, and said other end member being provided on its outer surface with a thread. and a threaded clamping member adapted to bring said end members into tight engagement.

4. A coupling means for outer conductor sections of a coaxial cable; said coupling means comprising two end members; each of said end members being adapted to be connected with one end of outer conductor sections to be joined; one of said end members being provided with an end piece having an inwardly tapering conical portion and an adjacent cylindrically shaped portion; the other of said end members being provided with a registering outwardly tapering conical bore and an adjacent cylindrical bore, said conical and cylindrical bore being adapted to receive and guide said inwardly tapering conical, and the adjacent cylindrical portions; the angle formed by the conical surface in the end piece of said one of the end members and the cylindrical inner surface thereof, being slightly smaller than the angle formed by the surface of said conical bore and the cylindrical inner surface of said other end member; a contact between the assembled end members being formed at the tips of their conical end portions; the inner surfaces of the outer conductor sections, and the inner surfaces of the end members being adapted to form an unbroken, cylindrical surface having substantially the same inner cross-section throughout the outer conductor sections and the cylindrical portions; the

coupling means; means adapted to bring said end members into tight engagement.

5. A coupling means for outer conductor sections of a coaxial cable; said coupling means comprising two end members; each of said end members being connected with one end of outer conductor sections to be joined; one of said end members being provided with an end piece having an inwardly tapering conical portion and an adjacent cylindrically shaped portion; the other of said end members being provided with a registering outwardly tapering conical bore and an adjacent cylindrical bore, said conical and cylindrical bore being adapted to receive and guide said inwardly tapering conical, and the adjacent angle formed by the conical surface in the end piece of said one of the end members and the cylindrical inner surface thereof, being slightly smaller than the angle formed by the surface of said conical bore and the cylindrical inner surface of said other end member; said one end member being also provided with a recess adapted to receive a projection of said other end member, and to receive packing means between said projection and the surface of said recess; a contact between the assembled end members being formed at the tips of their conical end portions; the inner surfaces of the outer conductor sections, and the inner surfaces of the end members being adapted to form an unbroken, cylindrical surface having substantially the same inner cross-section throughout the outer conductor sections and the coupling means; means adapted to bring said end members into tight engagement.

6. A coupling means for outer conductor sections of a coaxial cable, said coupling means comprising two end members, each of which is adapted to be connected with one end of outer conductor sections to be joined, one of said end members being provided with an end piece having an inwardly tapering conical portion and an adjacent cylindrically shaped portion, the other of said end members being provided with an out- 3 wardly tapering conical bore and an adjacent cylindrical bore, said conical and cylindrical bores being adapted to receive and guide said inwardly tapering conical and the adjacent cylindrical portions, the angle formed by the conical surface in the end piece of said one of the end members and the cylindrical inner surface thereof, being slightly smaller than the angle formed by the surface of said conical bore and the cylindrical inner surface of said other end member, a contact between the assembled end members being formed at the tipsof their conical end portions, said end members being provided with flanges having abutting portions, and means adapted to bring said end members into engagement.

7. A coupling means for outer conductor sections of a coaxial cable, said coupling means comprising two end members, each of which is adapted to be connected with one end of outer conductor sections to be joined, one ofsaid end members being provided with an end piece having an inwardly tapering conical portion and an adjacent cylindrically shaped portion, the other of said end members being provided with an outwardly tapering conical bore and an adjacent cylindrical bore, said conical and cylindrical bore being adapted to receive and guide said inwardly tapering conical and the adjacent cylindrical portion; the angle formed by the conical surface in the end piece of said one of the end members and the cylindrical inner surface thereof, being slightly smaller than the angle formed by the surface of said conical bore and the cylindrical inner surface of said other end member, said-end members being provided with flanges having abutting portions, one of said end members being also provided with a recess adapted to receive a projection of the other end member, and to re-- ceive packing means between said projection and the surface of said recess, a contact between the assembled end members being formed at the tips of their conical end portions, and means adapted to bring said end members into engagement.

WILLIAM A. BRUNO. 

